Research Projects

My research is chiefly concerned with reconstructing changes in ocean physics, chemistry, and patterns of variability on both long-term and human-relevant timescales. I combine geochemical measurements on marine microfossils with statistical and global climate models to assemble a process-oriented understanding of the ocean's role in global climate change.

My partnerships with colleagues extends this core focus to other natural archives and other climate periods deeper in Earth's history. I also maintain collaborations with environmental scientists to assist in contaminat monitoring.

Learn more about my ongoing projects below!

PLIOD

"Pliocene Lessons for the Indian Ocean Dipole"

Climate variability in the tropical Indian Ocean influences some of the most densely population regions of the planet. From the crop-sustaining monsoons to the seasonally-productive waters nurturing key fisheries, understanding how Indian Ocean variability will change in the future is critical for ensuring the welfare of nations around the basin. A recent study found that during the Last Ice Age, the region hosted a large pattern of variability that does not exist today—one that resembles the Pacific's El Niño. Global climate models suggest this "Indian Niño" will re-emerge as carbon emissions warm the planet. Is there a historical analogue we can turn to to test these model predictions? In collaboration with Heather Ford (Queen Mary University of London), Kaustubh Thirumalai (University of Arizona), and others, I am reconstructing Indian Ocean variability during the Pliocene epoch, a climate period that resembles our future climate under a middle-of-the-road emissions scenario. If we find evidence of the Indian Niño akin to what was found during the Last Ice Age, we can ensure that future projections capture this emergent climate pattern and mitigation/adaptation strategies adequately prepare for its associated impacts.

Ryan Glaubke sectioning a sediment core on the deck of the R/V Thomas G. Thompson. Cassie Stirpe and Yingxin Kou look on.

CROCCA-2S

"Coring to Reconstruct Ocean Circulation and Carbon dioxide Across 2 Seas"

Over the last 1 million years, atmospheric carbon dioxide (CO2) has closely tracked global climate, gradually decreasing when Earth descended into Ice Ages and rapidly rising during Earth's glacial terminations. The ocean is at the heart of this dance between carbon and climate. Through a series of processes known as the Biological Pump, CO2 is removed from the atmosphere and stored in the deep ocean. During Ice Ages, the circulation responsible for "turning over" these carbon-rich waters slows down, allowing for a build up of CO2 in the ocean interior at the expense of the atmosphere. When ocean circulation reinvigorates during deglaciations, that water is brought to the surface once again, where it "exhales" the CO2 back into the atmosphere. The epicenter of this exchange is the Southern Ocean around Antarctica, but the exact mechanisms that facilitate this CO2 release, as well as its pace and timing, remain an open question. Prior work has shown that CO2 release from the deep Atlantic and Pacific were not synchronous, with the Pacific leading by several millennia. This has led some to suggest that Southern Ocean dynamics play an active role in CO2 release and deglacial warming, challenging the conventional view that Atlantic circulation drives deglacial change. But what was the Indian Ocean doing? Did it also release CO2? When, and how quickly? And does this CO2 release appear to be in response to forcing in the Northern or Southern Hemisphere? To address these questions, we sailed to the Indian sector of the Southern Ocean aboard the R/V Thomas G. Thompson in 2018. Insights from this cruise will not only help us better understand deglacial climate dynamics but also how the ocean retains and releases carbon, with direct relevance for long-term climate projections and marine carbon dioxide removal strategies.

A photo of the science team aboard the R/V Thomas G. Thompson during the CROCCA-2S Expedition in the south Indian Ocean.

A map of the cruise track and sampling locations during the CROCCA-2S expedition in the south Indian Ocean.

Other Collaborations

Reconstruction of Indian Summer Monsoon intensity over the Last Millennium using Indian speleothems (Lead: Aniket Dhar, University of Arizona).
Assembling a global network of Miocene sea surface temperature estimates using foraminiferal Mg/Ca (Lead: Weimin Si, Brown University).
Pinpointing sources of uranium and arsenic contamination in Navajo Nation well waters (Lead: Anu Sethuraman, University of Arizona).

Ryan Glaubke with his watch aboard the R/V Atlantis in the North Atlantic Ocean.